Exercise bicycle



FIG. 1 is a front elevational view of an exercise bicycle showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a top, front and right side perspective view thereof; and,

FIG. 7 is a top, rear and left side perspective view thereof.

The broken lines in the drawings illustrate portions of the exercise bicycle which form no part of the claimed design. 

CLAIM The ornamental design for an exercise bicycle, as shown and described. 